Because of global climatic changes, air pollution and the gradual shortage of resources, solar power for using as a source of energy supply has attracted our attention, which leads to the rapid growth of solar cell market in the recent years.
A common and conventional solar cell has a P-N junction formed adjacent to its front surface or its light receiving surface. When the solar cell absorbs solar energy, the P-N junction generates electrons/electron-holes for outputting an electric current to the solar cell. A conventional design of the solar cell has an N-pole electrode disposed on a front side (light receiving side) of the solar cell, and a P-pole electrode disposed on a back side (non light receiving side) of the solar cell.
Another design of the solar cell is to have both the N-pole electrode and the P-pole electrode disposed on the back side of the solar cell. It is commonly called a back contact solar cell. The back contact solar cell can have both the solar cell and a solar cell circuit encapsulated in a single manufacturing process.
The technology for encapsulating a back contact solar cell is high electric generation and low encapsulating loss, and the output electric current can be enhanced by disposing both the electrodes on the back side. However, the problem of stress in tandem connection should be considered. Furthermore, the manufacturing processes of module may increase the risks of ineffective tandem connection and cell fragmentation. Also, ways to enhance the photoelectric conversion efficiency should be taken into consideration. Therefore, related researches on the issues are highly demanded.